The design of bicycle seats has evolved to reduce the weight, thickness and bulk of the seats. Also, there has been a major emphasis on relieving pressure in the perineal area (between the anus and the genitals), in order to prevent pain, genital numbness, occlusion of blood-flow and penile dysfunction. As the areas of relief, usually in the form of a cutaways, have expanded, there has been a resulting trend toward loading the majority of the bicycle rider's weight on the ischial tuberosities (ischials or seat bones).
The tendency to load more and more pressure on the ischials is further heightened by two factors. First, the upright sitting posture of mountain bikes and hybrid bikes results in a more vertical contact of the ischials against the saddle. When the rider leans forward on a racing bike, the ischials point more to the rear and take less pressure, but the upright posture increases ischial pressure. Second, as people age, the tissues and muscles beneath the ischials tend to atrophy or waste away, making the ischials protrude more and take more pressure.
As a result, more and more riders suffer some degree of pain at the ischials, particularly during bike rides of an hour or more. To help mitigate this, riders are taught to shift weight and stand on their pedals regularly. Others use salves to reduce chafing. For some riders, the pain becomes intense enough that they have to stop riding. Others develop saddle sores or swelling on the ischials that is indicative of ischial bursitis (an inflammation of the bursal sac located in the gluteal region).
Another area of common abrasion and chafing lies in the bone structure (pubis) forward of the ischials, as they also scrape and abrade against the saddle during riding. This is particularly true for women who tend to put more pressure on the pubic bones, about 7 cm forward of the ischial tuberosities. Large numbers of women have given up cycling because of this pain. Similar increased pressure is also experienced by men riding in the racing position.
It would be advantageous if an improved bicycle seat could be developed.